Here we will explain you how to close the property or just some rooms via web for specific period of the year.
Log in to the system on https://app.otasync.me
Then go to Calendar > Prices & Restrictions > Option Closure on bottom (image bellow)
Then choose period you would like to do closure for and select room type or all room types and choose under 'Stop Sell' to 'Closed' (image below)
And that is it, you will see on the diagram right that your chosen period is now red which means it is closed.
To reopen closed periods everything is the same as per the instruction above just now instead 'Stop Sell : Closed' you choose 'Stop Sell: Opened'.